btrfs: print-tree: add generation and type dump for EXTENT_DATA_KEY

btrfs: print-tree: add generation and type dump for EXTENT_DATA_KEY

When debugging the recent ram_bytes mismatch bug, I can hit it with
enhanced tree-checker for file extent items at write time.

But the bug is not that easy to trigger (mostly triggered with
btrfs/06*, which uses 20 threads fsstress), and when I hit it, the only
info is the kernel leaf dump, but it doesn't include things like the
file extent type (REGULAR or PREALLOC).

Add the dump for generation and type (although only numeric output) to
make debugging a little easier.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>